The present invention relates to an optometric apparatus for examining the visual function of an eye to be examined.
In a case where a refractive error is present in an eye to be examined, and a correction power is to be obtained for correcting the same, a subjective examination is carried out in which, by using a subjective-type examination unit in which corrective optical systems having various optical characteristics are selectively disposed in test windows, the corrective optical system is changed over while obtaining from a subject responses on appearances of presented test targets, so as to adjust the correction power.
In conducting this subjective examination, the examination is generally effected by initializing the corrective optical systems which are based on objective value data obtained by a device for objectively measuring the refractive power or on data on the values of spectacles which were worn by the subject. In a case where the corrective optical system is to be changed during the examination, there are cases where there arises a need to confirm the data on which the corrective optical system is based. In addition, to conduct an accurate examination, it sometimes becomes necessary to confirm not only the data which served as the basis of the initialization, but also the spectacle value data and unaided visual acuity values. In particular, in a stage where prescription power are adjusted, in the light of optimum prescription it is essential to adjust the powers while making a comparison between the perfect correction values and the spectacle values.
Among the conventional apparatuses, an apparatus is known which is provided with the function of simultaneously displaying on a display the measured data in a present measurement mode and the measured data in the last measurement mode. This apparatus is adapted to selectively dispose corrective optical systems in the test windows of the subjective-type examination unit in correspondence with the measured data in the present measurement mode.
However, the above-described apparatus allows only the present measured data and the immediately preceding measured data to be viewed simultaneously. In order to view other data, it is necessary to select a measurement mode and change it over. At this time, corrective optical systems which correspond to the changed-over measurement mode are disposed in the test windows of the subjective-type examination unit, so that the testing efficiency is not satisfactory.
In addition, in a case where it is necessary to view a plurality of items of data, there are cases where data which have been printed out by an objective-type refractive power measuring device or a lens meter are used, or a chart to which such data have been transcribed is used. However, these forms are difficult to manage, and there are cases where charts which have transcription errors or erroneous print-outs are adopted.